Tuesday, October 20, 2015

Last week we talked about ice ages. Today I will try to explain what causes ice ages and are we heading for another one at this time? We start out with the time period known as
the Pleistocene epoch. Pleisto means most recent. It is typically defined as the time period
that began 1.8 million years ago and lasted until about 11,700 years ago. The most recent ice age occurred then, as
glaciers covered huge parts of the planet Earth. There have been at least five documented
major ice ages during the nearly 5 billion years since the earth was formed. At
one point, during the recent ice age, sheets of ice covered all of Antarctica,
large parts of Europe, North America and South America and small areas in Asia.
In North America the ice stretched over Greenland and Canada and parts of the
northern United States. The remains of
glaciers of the latest ice age can still be seen in parts of the world,
including Greenland and Antarctica. During
this time there were about 20 cycles when the glaciers would advance and
retreat as they thawed and refroze.

So
what are some of the theories put forth to explain ice ages? The consensus is that several factors are
important. One that has been put forth is the change in the earth’s atmosphere.
During the recent period of the last 100-1000 years, the sharp increases in
human activity, especially the burning of fossil fuels, has caused the parallel
sharp and accelerating increase in atmosphere greenhouse gases which trap the
sun’s heat. Some scientists feel the resulting gases cause the increase in
global warming and thus the chief contributor to the accelerated melting of the
remaining glaciers and polar ice.

Others
say the activities of the human species first began not in the 18th
century with the advent of the industrial era, but dates back to 8,000 years
ago, due to intense farming activities of our early ancestors. It was at that time that atmospheric
greenhouse gas began to increase. Some
say it was the introduction of large-scale rice agriculture in Asia, coupled
with extensive deforestation in Europe that caused the warming of the
atmosphere during the last 1000 years.
Warmer climate caused warmer ocean waters and thus less efficient
storehouses of carbon dioxide. Theories,
theories, theories! The
geological records also appear to show ice ages start when continents are in
positions which block or reduce the flow of warm water from the equator to the
Poles and thus allow ice sheets to form. The ice sheets increase earth’s
reflectivity and thus reduce the absorption
of solar radiation. The earth cools, ice
sheets continue to grow which further increases reflectivity and the cycle
continues. Another
popular theory is variations in earth’s orbit
(Milankovich’s theory.) Of particular importance are the changes in the tilt
of the earth’s axis, which affect

the
intensity of seasons. It is widely
believed that ice sheets advance when summers become too cool to melt all of
the accumulated snowfall from the previous winter. Of course, this is just
another theory and not completely accepted by the scientific community.
However, it does make a lot of sense.
Another theory is that the sun outputs varying amounts of energy.
Scientists are skeptical about this theory. They think the variation in the
sun’s output is so small as to have little effect on our climate.

How
about volcanism? Could volcanic
eruptions be the cause of ice ages?
Volcanoes can contribute to high amounts of carbon dioxide in the
atmosphere when they erupt. Carbon
dioxide from volcanoes probably contributed to periods with highest overall
temperatures. With regard to volcanoes,
they also spew tremendous amounts of soot and ash into the atmosphere. This can circulate around the globe in the
upper atmosphere for years and years.
Could this block out the radiation from the sun and cause an ice age?
Many, many questions, very few answers.
Remember, ice ages last for millions and millions of years. I believe the cause or causes of such
occurrences have to be long lasting. If
one wanted to press me for my thoughts, I would have to think the variations in
the earth’s orbit around the sun, (Milankovich theory) has the most
credibility. This may work in coordination with other factors to bring on an
ice age.

We talked about the year without a summer, 1816.
Periodically we have periods of cold weather but that is not an ice age. By definition, an ice age is a
period of long-term reduction in the temperature of the earth’s surface and
atmosphere, resulting in the presence or expansion of continental and polar ice
sheets and alpine glaciers. Within a long-term ice age, there are intermittent
warm periods we call interglacial periods.We are in an interglacial period right now.

Before we go too far into the talk on ice ages, it is
important to put “time” into perspective.I really don’t know when our universe was created, the so-called “big
bang”.Theory has it our sun was born
approximately 15 billion years ago.Our
earth came into being some 5 billion years ago. When did man make his
appearance on earth?Well, let’s shrink
the earth’s 5 billion year history into a single year.Man did not appear in January, not even the
beginning of December. On December 15th man still has not appeared on
earth.Not even on December 30th.On December 31st at noon time, man is still
not present.At 11 pm, no sign of
man.At 11:59 pm still no sign of
man.The final seconds tick off on New
Year’s Eve.11:59 and 50 seconds, no
man.Finally, at 11:59 and 59 seconds
man appears on earth.Out of the entire
year, man has existed on earth for only one second.Having this in mind, it is easier to
understand ice ages.

Let’s go way back…during the past billion (that’s a b)
years, the earth has fluctuated between warm periods (even ice free) and cold
periods when glaciers scoured the continents. The current earth cooling started
about 70 million years ago and continues today.We can determine that by examining marine sediments.We have a fairly continuous record of earth’s
climate change. This record indicated decreasing deep-water temperatures along
with the build-up on continental ice sheets.Much of the deep-water cooling occurred in three major steps…36, 15 and
3 million years ago…the most recent continues today.Filling in the blanks, between 20 & 16
million years ago the earth warmed up.About 7 million years ago the glaciers began to grow and by 5-6 million
years ago glaciers continued to grow. Then came a warming period between 5
& 3 million years ago.In fact,
during that period it became much warmer than it is today...

Seems like a long time to us, but geologically speaking it
is only the blink of the eye.Then about
3 million years ago, temperatures started falling as we entered another
glaciation period.We are still in the
midst of the third major cooling period.During this time, glaciers have advanced and retreated over 20 times,
often blanketing portions of North America with ice.Our climate today is actually a warm period
between these many periods of glaciation.The most recent period of glaciation, which many people think of as “the
ice age” was at its height approximately 20,000 years ago. About 10,000 years
ago, the earth began to warm up.Currently, all that remains of the continental ice sheets are the
Greenland and Antarctic ice sheets and a few smaller glaciers.A typical interglacial period lasts about
12,000 years.Are we about ready to
begin to slide into another glaciation period?Scientists differ on this.Some
say it is just around the corner, others say it is 28,000 years off, others say
it is 50,000 years in the future.

We should consider ourselves extremely lucky.The majority of the time, the earth is in the
midst of “an ice age”.Everyone living
on earth today has been blessed with, as they say, a “friendly sun”.

The question always comes up about climate change.Does the climate change?Of course it does.Are human beings responsible for these changes?Well, as mentioned earlier in this blog, many
times in the past the earth has been much warmer than it is today.Mankind was not around to cause that warming.
Perhaps we can influence the climate to a small degree, but I think climate
changes because of factors way beyond our control. Could we stop the tide from
coming in?Could we stop lava from
coming out of a volcano?Could we change
the course of a hurricane?No, of course
not.Climate change occurs over millions
and millions of years.

Next week I will examine some of the theories put forth
explaining the causes of ice ages.None have been so plausible as to be able to predict the
next ice age.

Thursday, October 15, 2015

Last
time we talked about the hurricane, how and where it formed (over warm ocean
waters).We mentioned hurricanes
generally form from June 1 through November 30th in the Atlantic and
May 1 to November 30th in the Pacific Ocean.We talked about the surge of water that comes
ashore with a hurricane, the storm surge and then mentioned the scale that
measures the strength of hurricanes called the Saffir-Simpson.Today we are going to investigate these
storms a little more.

I
get asked this question many, many times.What is the difference between a hurricane, a typhoon and a
cyclone?The answer is, basically
nothing except location.In the Atlantic
Ocean, the Gulf of Mexico and the eastern Pacific Ocean, these tropical storms
are known as hurricanes.In the western
Pacific Ocean, these same storms are called typhoons and in the Indian Ocean,
the Bay of Bengal and Australia these storms are called cyclones. So, same type
storm, just named differently in different parts of the world.

Years
ago, there were no satellites, no radar, no TV, not even radios.The major hurricane that hit Galveston, Texas
in 1900 took the public by complete surprise.There were a few reports being spread around that Cuba had a hurricane
but that “news” was dismissed as hearsay.While this storm was approaching Galveston, many curious folks went to
the seashore to examine the angry seas.Finally, the storm surge arrived on shore and washed thousands of
onlookers out to sea.In all, when the
storm had passed, 16,000 people had lost their lives.Today, that would never happen.We have come so much further than back in
those days.In the 1950’s hurricane
hunter planes began flying into the eyes of hurricanes.One of my high school students, who was part
of the weather club I organized at the high school, is now the director of
research of the national hurricane center.He is in charge of the hurricane hunter division.He has asked me numerous times to fly with
him into a hurricane on the hurricane hunter plane.I refuse each time because I am chicken.He does tell about some harrowing experiences
he has had, but insists they have never had a passenger death or lost a
hurricane hunter in over 60 years of flying into hurricanes. My student tells
of his experiences, saying the flight is 95% boredom and 5% sheer terror.Anyway, he has flown though the eye of
hurricanes over 300 times.These
hurricane hunter planes usually fly into, through and around the eye of the
hurricane at all levels to get very accurate readings concerning the storm and
then send all the data back to the hurricane center where it is put into
computers to improve the forecast of the future speed, strength and direction
of the storm.

Of
course, also being relayed back to the hurricane center are pictures of the
storm from space.Satellite imagery has
improved greatly over the years.As the
storm gets closer to land, radar is then utilized.Now they can get an exact fix on the location
of the storm and track its exact movement.Forecasts are then made and ready for distribution.Again, one of my students from the high
school weather program is the executive vice president of the largest weather
corporation in the world.Millions and
millions of people are notified immediately by radio, TV, and internet that a
storm is threatening their location.Mandatory evacuations are issued in areas that are in eminent
danger.Never again will a hurricane
“sneak up” on a location.When storms
are just beginning, they are picked up by the satellites and followed.When then get closer to land, the planes fly
out to examine them.Then radar goes
into play.Computer programs forecast
future movements…. we are well protected…. follow the watches and
warnings.

Usually
a watch means a weather situation is possible in the next 12-36 hours.A warning means a weather situation is
expected in the next 24 hours.For
example, a hurricane warning means hurricane conditions are expected in your
area within 24 hours and all precautions should be taken immediately, including
evacuation if necessary.Within the last
10-20 years, beachfront property has become a very popular location.A major hurricane, category 4 or 5 will be
catastrophic. Some people will refuse to evacuate, others may be unable to
evacuate.Time will tell how this is
going to work out.There are indications
a major hurricane may threaten the east coast of the United States from
September 17th to 19th, 2015.That’s this year!Of course,
making an outlook like this is like shooting a bullet out of the sky with
another bullet, but we will watch.